1. Field of the Invention
This invention relates to an over-the-needle I.V. catheter. More particularly, this invention relates to a closed system over-the-needle intravenous catheter.
2. Description of the Prior Art
The problem of providing an infusion device for a patient has been addressed in several patents, among which are U.S. Pat. Nos. 3,851,647; 4,073,297; 4,311,137; 3,313,299; 4,037,595; 4,016,879; 3,875,938; 4,496,348; 4,531,937 and 4,529,399.
It is to be noted that the U.S. Pat. No. 4,311,137, identified above, although providing a needle, flash-back indicator, side arm and catheter and providing wings for securement, initially has the catheter 18 extending beyond the needle tip of the needle 76. This catheter end beyond the piercing end of the needle during sterilization, storage and shipment usually bends sufficiently so that the catheter is cut when the needle is pushed forwardly for penetration of the skin of the patient. This is highly undesirable. As described, the air is vented beside the seal-off plug and fluid comes out by the needle holder. This is not a "closed system" in that fluid as it is fed into the hub to purge air has the fluid and air open to the atmosphere as and when the device is unwrapped for use. The teaching of this patent is that the needle is advanced by the attendant to extend beyond the catheter tip. When and as the needle is advanced within the catheter and without assembly apparatus as provided by an assembly machine, the alignment of the catheter and needle must be very precise. Otherwise, the sharpened end of the needle cuts the flexible plastic catheter. The practitioner has no such assembly alignment apparatus. The seal assembly is initially vented to atmosphere, then the needle holder is moved forward to exert a side compressive force provided by the formed taper.
U.S. Pat. No. 3,851,647, although having a catheter over a needle, anticipates sealing of the needle hole with a resilient flap. U.S. Pat. No. 4,073,297 also provides a rubber plug as a seal of the withdrawn needle. The opposed openings 20 in the catheter are not very tiny so as to exclude an inflow of blood to and into the interior of the catheter. The plug 38 is removable, but clamping of portion 36 is effected to exclude fluid and blood flow. U.S. Pat. No. 3,313,299 relies on resilient plug 30 for a seal after the trocar 48 is withdrawn. In U.S. Pat. No. 4,531,937, the expelling of air is through plug 30 and there is no assurance of purging of the air unless the catheter 18 has an open entering end, which is not desired. U.S. Pat. No. 4,496,348 utilizes a spring to exert a force on the rubber seal after needle withdrawal. In sterilization and storage, this spring exerts a force on the rubber plug 30 and causes a small binding to develop which results in adherence of this rubber to the needle and requires excessive force for removal of the needle from this plug. For this reason, the product is currently not available nor has the problem of air purging been addressed.
Also of note are U.S. patents directed to the use of resilient sealing of a needle shank and providing a desired seal of the passage of the withdrawn needle shank. Among these patents are: U.S. Pat. Nos. 4,610,674; 4,610,665; 4,177,814; 4,626,245 and 4,430,081. These proposed sealing procedures anticipate prior seal sterilization and storage. Positioning of the trocar through the seal is just prior to or during use.
In the patents noted above and showing a catheter over the needle and as connected to an administration set and prior to puncture of a blood vessel, a deficiency exists as there is no complete removal procedure for insuring that air present is completely purged from the system.
In known systems, intravenous fluid administration devices often include a holder carrying a plastic catheter and a removable needle cannula extending through the catheter and past the distal tip of the catheter for inserting the needle and catheter through the skin and into a body vessel, such as a vein of a patient. If the venipuncture is successfully performed, the needle is removed and a source of infusion liquid, such as glucose, blood, saline solution or other liquid, is connected to the holder to supply the infusion liquid to the vein.
Air must, of course, be removed from the catheter placement device, and the infusion liquid source connected to it without introducing air into the device in order to avoid any air being introduced into the vein of the patient. Generally, after the venipuncture and removal of the needle, blood is allowed to flush the air from the catheter holder, and a liquid-filled delivery tube from the infusion liquid source is then carefully connected to the blood-filled device.
Performing the above steps without introducing air into the system is relatively tedious, and generally results in blood escaping from the device and soiling clothing or the like or requiring the use of absorbent materials to catch the escaping blood. Also, the above connection of the infusion liquid source to the device requires manipulation of parts while the catheter is in the vein of the patient, and this tends to increase patient discomfort and the danger of damage to the patient. This procedure is shown in FIG. 1 and identified as Prior Art.
The most popular I.V. Catheter used today is known as an over-the-needle catheter. In excess of seventy percent of all I.V. catheters are placed using this technique. The major advantages claimed for this produce are: its ease of insertion and the ability to be placed in peripheral veins. The major disadvantage is having to connect a pre-primed I.V. administration set to the catheter hub. This requires manipulation and/or dexterity. Numerous journal articles have addressed the question of contamination resulting from this procedure. It is generally believed that a significant percentage of the incidences of sepsis is directly attributed to this manipulation. With the advent of AIDS and its potential for communicating the disease by way of the bloodstream, the need for performing "bloodless" venipuncture has become more acute.
The above-noted prior art is deficient in a number of areas. It does not provide for a simple, effective means for removing all air from the systems prior to insertion of the catheter into a patient. This is essential to provide a safe product. Means is not provided for minimizing drag of the needle during removal whereat and whereby the practitioner is able to readily remove the needle from the catheter without disturbing the positioning of the catheter in a blood vessel (usually a vein) and concurrently seal off the passage. The above and known patents and devices do not provide an effective and positive seal of the passageway during removal of the needle. U.S. Pat. No. 4,496,348 is only directed to a seal of the hole left by the withdrawal of the needle, but this constant spring force causes a welding or excessive friction to be developed which disturbs a smooth insertion procedure and use.
In the summary immediately below, in the description and in the claims, that member to which the catheter is attached is identified as "hub" and that member to which the needle is secured is identified as "holder."